Establishment of Wolbachia infection in Aedes aegypti from Pakistan via embryonic microinjection and semi-field evaluation of general fitness of resultant mosquito population

Background Dengue is a mosquito-borne viral disease that is mainly spread by Aedes aegypti . It is prevalent on five continents, predominantly in tropical and sub-tropical zones across the world. Wolbachia bacteria have been extensively used in vector control strategies worldwide. The focus of the current study was to obtain a natural population of Ae. aegypti harbouring Wolbachia and to determine the impact of this bacteria on the new host in a semi-field environment. Methods Wolbachia -infected Aedes albopictus was collected from the city of Lahore, Punjab, Pakistan, and Wolbachia were successfully introduced into laboratory-reared Ae. aegypti via embryonic microinjection. The stable vertical transmission of w AlbB in the host population was observed for eight generations, and the impact of Wolbachia on the general fitness of the host was evaluated in semi-field conditions. Results In the laboratory and semi-field experiments, w AlbB Wolbachia presented a strong cytoplasmic incompatibility (CI) effect, evidenced as zero egg hatching, in crosses between Wolbachia -infected males and wild (uninfected) females of Ae. aegypti . Wolbachia infection had no noticeable impact on the general fitness ( P > 0.05), fecundity, body size (females and males) and mating competitiveness of the new host, Ae. aegypti . However, there was a significant decrease in female fertility (egg hatch) ( P < 0.001). In addition, under starvation conditions, there was a remarkable decrease ( P < 0.0001) in the life span of Wolbachia -infected females compared to uninfected females (4 vs. > 5 days, respectively). Conclusions Wolbachia strain w AlbB has a great potential to control the dengue vector in Ae. aegypti populations by producing 100% CI with a limited burden on its host in natural field conditions. This strain can be used as a biological tool against vector-borne diseases. Graphical Abstract